// deno-lint-ignore-file no-var
// base74-js 1.5.1
var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array

var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var i = 0, len = code.length; i < len; ++i) {
    lookup[i] = code[i]
    revLookup[code.charCodeAt(i)] = i
}

// Support decoding URL-safe base64 strings, as Node.js does.
// See: https://en.wikipedia.org/wiki/Base64#URL_applications
revLookup['-'.charCodeAt(0)] = 62
revLookup['_'.charCodeAt(0)] = 63

function getLens(b64) {
    var len = b64.length

    if (len % 4 > 0) {
        throw new Error('Invalid string. Length must be a multiple of 4')
    }

    // Trim off extra bytes after placeholder bytes are found
    // See: https://github.com/beatgammit/base64-js/issues/42
    var validLen = b64.indexOf('=')
    if (validLen === -1) validLen = len

    var placeHoldersLen = validLen === len
        ? 0
        : 4 - (validLen % 4)

    return [validLen, placeHoldersLen]
}

// base64 is 4/3 + up to two characters of the original data
function byteLength(b64) {
    var lens = getLens(b64)
    var validLen = lens[0]
    var placeHoldersLen = lens[1]
    return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function _byteLength(b64, validLen, placeHoldersLen) {
    return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function toByteArray(b64) {
    var tmp
    var lens = getLens(b64)
    var validLen = lens[0]
    var placeHoldersLen = lens[1]

    var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen))

    var curByte = 0

    // if there are placeholders, only get up to the last complete 4 chars
    var len = placeHoldersLen > 0
        ? validLen - 4
        : validLen

    var i
    for (i = 0; i < len; i += 4) {
        tmp =
            (revLookup[b64.charCodeAt(i)] << 18) |
            (revLookup[b64.charCodeAt(i + 1)] << 12) |
            (revLookup[b64.charCodeAt(i + 2)] << 6) |
            revLookup[b64.charCodeAt(i + 3)]
        arr[curByte++] = (tmp >> 16) & 0xFF
        arr[curByte++] = (tmp >> 8) & 0xFF
        arr[curByte++] = tmp & 0xFF
    }

    if (placeHoldersLen === 2) {
        tmp =
            (revLookup[b64.charCodeAt(i)] << 2) |
            (revLookup[b64.charCodeAt(i + 1)] >> 4)
        arr[curByte++] = tmp & 0xFF
    }

    if (placeHoldersLen === 1) {
        tmp =
            (revLookup[b64.charCodeAt(i)] << 10) |
            (revLookup[b64.charCodeAt(i + 1)] << 4) |
            (revLookup[b64.charCodeAt(i + 2)] >> 2)
        arr[curByte++] = (tmp >> 8) & 0xFF
        arr[curByte++] = tmp & 0xFF
    }

    return arr
}

function tripletToBase64(num) {
    return lookup[num >> 18 & 0x3F] +
        lookup[num >> 12 & 0x3F] +
        lookup[num >> 6 & 0x3F] +
        lookup[num & 0x3F]
}

function encodeChunk(uint8, start, end) {
    var tmp
    var output = []
    for (var i = start; i < end; i += 3) {
        tmp =
            ((uint8[i] << 16) & 0xFF0000) +
            ((uint8[i + 1] << 8) & 0xFF00) +
            (uint8[i + 2] & 0xFF)
        output.push(tripletToBase64(tmp))
    }
    return output.join('')
}

function fromByteArray(uint8) {
    var tmp
    var len = uint8.length
    var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
    var parts = []
    var maxChunkLength = 16383 // must be multiple of 3

    // go through the array every three bytes, we'll deal with trailing stuff later
    for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
        parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)))
    }

    // pad the end with zeros, but make sure to not forget the extra bytes
    if (extraBytes === 1) {
        tmp = uint8[len - 1]
        parts.push(
            lookup[tmp >> 2] +
            lookup[(tmp << 4) & 0x3F] +
            '=='
        )
    } else if (extraBytes === 2) {
        tmp = (uint8[len - 2] << 8) + uint8[len - 1]
        parts.push(
            lookup[tmp >> 10] +
            lookup[(tmp >> 4) & 0x3F] +
            lookup[(tmp << 2) & 0x3F] +
            '='
        )
    }

    return parts.join('')
}

export { byteLength, toByteArray, fromByteArray };